text: #
  # Licensed to the Apache Software Foundation (ASF) under one
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  # regarding copyright ownership.  The ASF licenses this file
  # to you under the Apache License, Version 2.0 (the
  # "License"); you may not use this file except in compliance
  # with the License.  You may obtain a copy of the License at
  #
  #   http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing,
  # software distributed under the License is distributed on an
  # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  # KIND, either express or implied.  See the License for the
  # specific language governing permissions and limitations
  # under the License.
  """Hook for Web HDFS"""
  import logging
  import socket
  from typing import Any, Optional
  
  from hdfs import HdfsError, InsecureClient
  
  from airflow.configuration import conf
  from airflow.exceptions import AirflowException
  from airflow.hooks.base_hook import BaseHook
  from airflow.models.connection import Connection
  
  log = logging.getLogger(__name__)
  
  _kerberos_security_mode = conf.get("core", "security") == "kerberos"
  if _kerberos_security_mode:
      try:
          from hdfs.ext.kerberos import KerberosClient  # pylint: disable=ungrouped-imports
      except ImportError:
          log.error("Could not load the Kerberos extension for the WebHDFSHook.")
          raise
  
  
  class AirflowWebHDFSHookException(AirflowException):
      """Exception specific for WebHDFS hook"""
  
  
  class WebHDFSHook(BaseHook):
      """
      Interact with HDFS. This class is a wrapper around the hdfscli library.
  
      :param webhdfs_conn_id: The connection id for the webhdfs client to connect to.
      :type webhdfs_conn_id: str
      :param proxy_user: The user used to authenticate.
      :type proxy_user: str
      """
  
      def __init__(self, webhdfs_conn_id: str = 'webhdfs_default', proxy_user: Optional[str] = None):
          super().__init__()
          self.webhdfs_conn_id = webhdfs_conn_id
          self.proxy_user = proxy_user
  
      def get_conn(self) -> Any:
          """
          Establishes a connection depending on the security mode set via config or environment variable.
          :return: a hdfscli InsecureClient or KerberosClient object.
          :rtype: hdfs.InsecureClient or hdfs.ext.kerberos.KerberosClient
          """
          connection = self._find_valid_server()
          if connection is None:
              raise AirflowWebHDFSHookException("Failed to locate the valid server.")
          return connection
  
      def _find_valid_server(self) -> Any:
          connections = self.get_connections(self.webhdfs_conn_id)
          for connection in connections:
              host_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
              self.log.info("Trying to connect to %s:%s", connection.host, connection.port)
              try:
                  conn_check = host_socket.connect_ex((connection.host, connection.port))
                  if conn_check == 0:
                      self.log.info('Trying namenode %s', connection.host)
                      client = self._get_client(connection)
                      client.status('/')
                      self.log.info('Using namenode %s for hook', connection.host)
                      host_socket.close()
                      return client
                  else:
                      self.log.error("Could not connect to %s:%s", connection.host, connection.port)
                  host_socket.close()
              except HdfsError as hdfs_error:
                  self.log.error(
                      'Read operation on namenode %s failed with error: %s', connection.host, hdfs_error
                  )
          return None
  
      def _get_client(self, connection: Connection) -> Any:
          connection_str = f'http://{connection.host}:{connection.port}'
  
          if _kerberos_security_mode:
              client = KerberosClient(connection_str)
          else:
              proxy_user = self.proxy_user or connection.login
              client = InsecureClient(connection_str, user=proxy_user)
  
          return client
  
      def check_for_path(self, hdfs_path: str) -> bool:
          """
          Check for the existence of a path in HDFS by querying FileStatus.
  
          :param hdfs_path: The path to check.
          :type hdfs_path: str
          :return: True if the path exists and False if not.
          :rtype: bool
          """
          conn = self.get_conn()
  
          status = conn.status(hdfs_path, strict=False)
          return bool(status)
  
      def load_file(
          self, source: str, destination: str, overwrite: bool = True, parallelism: int = 1, **kwargs: Any
      ) -> None:
          r"""
          Uploads a file to HDFS.
  
          :param source: Local path to file or folder.
              If it's a folder, all the files inside of it will be uploaded.
              .. note:: This implies that folders empty of files will not be created remotely.
  
          :type source: str
          :param destination: PTarget HDFS path.
              If it already exists and is a directory, files will be uploaded inside.
          :type destination: str
          :param overwrite: Overwrite any existing file or directory.
          :type overwrite: bool
          :param parallelism: Number of threads to use for parallelization.
              A value of `0` (or negative) uses as many threads as there are files.
          :type parallelism: int
          :param kwargs: Keyword arguments forwarded to :meth:`hdfs.client.Client.upload`.
          """
          conn = self.get_conn()
  
          conn.upload(
              hdfs_path=destination, local_path=source, overwrite=overwrite, n_threads=parallelism, **kwargs
          )
          self.log.debug("Uploaded file %s to %s", source, destination)
  